A vacuum cleaner is an electro-mechanical appliance utilized to effect the dry removal of dust, dirt and other small debris from carpets, rugs, fabrics or other surfaces in domestic, commercial and industrial environments. In order to achieve the desired dirt and dust removal, most vacuum cleaners incorporate a rotary agitator. The rotary agitator is provided to beat dirt and debris from the nap of the carpet or rug while a pressure drop or vacuum is used to force air entrained with this dirt and debris into the nozzle of the vacuum cleaner. The particulate laden air is then drawn into a dirt collection vessel. Next, the air is drawn through a filter before being directed through the motor of the suction generator to provide cooling. Finally, the air is filtered to remove any fine particles of carbon from the brushes of that motor or other dirt that might remain in the air-stream before being exhausted back into the environment.
While the rotary agitator is particularly beneficial in cleaning dirt and debris from the nap of a carpet or rug, it has long been known that the turbulence produced by a rapidly rotating agitator often interferes with the efficient cleaning of dirt and debris from a bare floor such as a hardwood or linoleum covered floor. Thus, for bare floor cleaning applications it is desirable to interrupt power to the rotary agitator. Where an upright vacuum cleaner incorporates a separate drive motor for the agitator, this is easily accomplished by simply de-energizing that dedicated drive motor. However, in order to lower production costs, minimize weight and reduce the size of an upright vacuum cleaner, many upright vacuum cleaners drive the rotary agitator through a power takeoff connected to the motor of the suction generator.
The interruption of the drive between the motor of the suction generator and the rotary agitator has taken many forms. Often, power is transmitted from the drive shaft of the suction generator motor to the agitator by means of a belt. In one approach a belt shifter is provided to shift the belt between the agitator drive pulley and an idler pulley to interrupt power transmission to the agitator. An example of just such an approach is disclosed in U.S. Pat. No. 5,768,746 to Kamatani et al. In yet another approach, an idler pulley is utilized to tension the drive belt to provide drive to the agitator and de-tension the drive belt to interrupt drive to the agitator. Such an approach is disclosed in, for example, U.S. Pat. Nos. 5,537,712 to Weber et al. and 6,915,544 to Roney et al.
The present invention relates to a floor care appliance or vacuum cleaner incorporating a new and improved agitator drive interrupt mechanism to more efficiently and effectively interrupt drive between the drive motor of the suction generator and the rotary agitator as desired by the operator.